By DAVE COLLINSHARTFORD, Conn. (AP) â¿¿ An amusement ride accident at a Connecticut fair that injured 12 children and an adult last month could have been prevented by routine maintenance, an official with the successor company of the ride's manufacturer said Thursday. The mishap occurred on the Zumur swing ride at the annual Oyster Festival in Norwalk on Sept. 8. A drive system that spins the ride's hanging swings suddenly froze, sending riders hurtling into each other and the ride itself. Thirteen people were brought to hospitals with minor injuries, and five others declined treatment at the scene. Crews later took apart the ride's hydraulic motor and discovered that a metal shaft that helps spin the ride had broken. The shaft, about 16 inches long and 2 inches in diameter, was attached to a gear that was hooked into another gear that helped propel the swings. Jeff Roth, vice president of administration for Chance Rides Inc. of Wichita, Kan., told The Associated Press that company determined that the shaft broke because the teeth on the gears had worn over the years and the gears hadn't been readjusted as they should have under manufacturer specifications. Chance's predecessor, Chance Manufacturing Co., made the ride in 1983. "It wore out over 30 years," Roth said. "Had it been kept properly adjusted, the accident wouldn't have happened." The ride that broke is owned by Stewart Amusement Co. of Monroe, Conn. The company's owner, Richard Stewart, said Thursday that his crews followed manufacturer specifications on maintenance and readjusting the gears wasn't part of those specifications, to their knowledge. "Once those things are set in place, they shouldn't have to be adjusted," Stewart said, referring to the gears. Stewart said he planned to call Chance Rides to discuss the problem. Roth said Chance Rides is sending out bulletins this week to owners of the remaining Zumur rides, advising them to check the gears and shafts in the motors for any problems using ultrasonic testing equipment. Roth says his company believes there about a dozen Zumur rides remaining in the U.S. and another three in other countries.